Multistrand windings with increased series capacitance

ABSTRACT

High series capacitance plural strand disk windings. The windings include an end portion whose turns are physically disposed in the following order starting with an end terminal: N plural turns of a first conductor, a single turn of a second conductor and M plural turns of the first conductor and the second conductors alternating sequentially. The winding may also include another portion, serially connected to the first mentioned portion and including plural turns physically disposed in the following order: one turn of the first conductor, R turns of the second conductor and S plural turns of the first and second conductors alternating sequentially. Windings including three or more conductors are constructed in similar manners.

United States Patent 1191 Crouse [11] 3,748,617 1451 July 24, 1973 MULTISTRAND WINDINGS WITH INCREASED SERIES CAPACITANCE Primary Examiner-Thomas J. Kozma Attorney-Francis X. Doyle et al.

[ 7] ABSTRACT High series capacitance plural strand disk windings. The windings include an end portion whose turns are physically disposed in the following order starting with an end terminal: N plural turns of a first conductor, a

[52] US. Cl. 336/70, 336/187 i l m of a ond conductor and M plural turns of [5 Int. the first conductor and the second conductors alternat- [58] Field of Search 336/69, 70, 186, m u ntially The winding may also include another 336/187 ortion, seriall connected to the first mentioned or- P Y P tion and including plural turns physically disposed in v ReferencesCiM the following order: one turn of the first conductor, R UNITED STATES PATENTS turns of the second conductor and S plural turns of the 3,348,182 /1967 Baker 3: al. 336/187 first and Second c o saltemating sequentially. 3,564,471 2/1971 Van Nice 336/187 x windings uding three or more conductors are con- FOREIGN PATENTS 0R APPLICATIONS strum manners 7 909,516 10/1962 Great Britain 336/186 4 Claims, 6 Drawing Figures f/L/A/E p p I MAB/ la .8c I361 /8c 23a 26 c 33a 40c 2a m //b .2016 V 2/3 305 VJ/b {Sc '1 3a /2a .90 22a /8c 32a A 29 aac lb 70 Ma 17 2461 27c Ja 016 461 .96 I26 /96 2216 1 2.96 32b 37c 26 //'.2 /0e 2/a c ala 38b Ja 6c lie /6'c 2f: A 260 1 a 36c 36 8b /36 m 236 286 3316 I J86 m /0a l/c 20a 2/6 30a a/ 40a 4 6a .32 /6a m 26a 26 36a an 416 as m m 241s 273 .m .373 20 8a /2c A913 22c 283 32c 3831 7a 4c /7a /4c 27a 24c 37a 34:: 56 X 66 m m, 2.53 V 236 an 36b 3c 8a m m 23 m 33:: 3a.; l 1 1 I (4o /4/ H2 H3 /44 H6 H6 H7 MULTISTRAND WINDINGS WITH INCREASED SERIES CAPACITANCE BACKGROUND AND OBJECTS OF THE INVENTION My invention relates to windings for electric induction apparatus such as transformers. The invention is directed particularly to means for improving voltage distribution throughout a winding and reducing the insulation stresses occurring therein upon application of steep wave impulse voltages such as lightning and switching surges. The following published art, now known to applicant, is exemplary of prior art approaches relevant in this area of technology: U.S. Pat. Nos. 2,453,552 (Steam); 3,221,282 (Brierley et al.); and 3,405,378 (Vincent-Martin).

In order to best appreciate my invention the following terms which are referred to in the specification will be defined hereinafter.

A disk coil; a plurality of radially stacked turns of one or more spiral conductors.

An interleaved or interlaced disk coil; a plurality of radially stacked turns of more than one conductor connected in a series circuit which traverses the coil more than once.

It is well known that highly inductive windings such as iron core transformer and reactor windings, when exposed to steep'wave front impulse or transient voltages, exhibit initially an exponential distribution of voltage drop along the length of the windings with a very high voltage gradient at the first few turns. For example, approximately 60 percent of the voltage may appear across the first percent of the turns of the winding at the high voltage end. This extremely nonuniform voltage distribution is due primarily to the unavoidable distributed capacitance between each incremental part of the winding and adjacent grounded parts such as the core and easing structure. Such ground capacitance is referred to as parallel" capacitance when the low voltage terminal of the winding is grounded in the usual manner. Such a winding inherently possesses also a distributive capacitance between turns, the sum of such capacitance being in series between the winding terminals. If this series capacitance alone were present, voltage distribution throughout the winding would be substantially uniform or linear, as it would be also if inductance alone were present. However, since distributed capacitance both series and parallel, is an inherent winding characteristic, voltage distribution in the presence of impulse voltages, such as lightning or switching surges, is a design consideration of importance. One common type of high voltage winding for transformers and reactors is a continuous disk winding. In such a winding each of a plurality of annular (disk) coils is wound as a radial spiral, the coils being disposed coaxially on a core and connected electrically in a seque'ntial series circuit relation with adjacent coils being wound in alternate rotational directions. As is known, continuous disk windings are characterized by relatively low series capacitance and as a consequence such windings have a relatively poor surge voltage distribution characteristic. Since the initial voltage distribution in a transformer winding subjected to a steepfronted voltage wave at a terminal thereof is a function of the ratio of the parallel capacitance (i.e., capacitance to ground) to the series capacitance of the winding, continuous disk windings are subject to insulation failure resulting from a poor initial voltage distribution in the event of a voltage surge.

The most practical way to improve the voltage distribution of a disk winding is to increase its series capacitance and many winding techniques are known for increasing such series capacitance. One disk winding technique is to utilize serially connected interleaved coils (see the above noted patents) so that mechanically adjacent turns are electrically remote from one another. non-sequential Although interlaced winding arrangements have a higher series capacitance than comparable continuous disk windings and therefore have improved voltage distribution capabilities, owing to their complex interlacing such windings are relatively expensive to construct; they necessitate relatively large amounts of conductor insulation and they are relatively voluminous. This is particularly true in plural-stranded, interlaced-disk windings.

It is a general object of my invention to provide a plural stranded disk winding which is simpler and less expensive to construct than a comparable interlaced disk winding.

In relatively large transformers the inside" or low voltage winding is commonly a continuous disk winding composed of plural parallel connected conductors or strands. As was previously noted continuous disk windings are subject to insulation failure upon the occurrence of surge voltages due to their low inherent series capacitance.

Accordingly, it is a further object of my invention to provide a plural stranded disk winding exhibiting a higher series capacitance than a plural-stranded, continuous-disk winding.

In my copending U.S. patent application, Ser. No. 210,997, filed on Dec. 22, 1971 and assigned to the same assignee as my instant invention, there is disclosed and claimed a relatively inexpensive and compact disk type winding which I call a Nonsequential Disk Winding." That winding is formed of a noninterlaced conductor whose turns are mechanically disposed in a non-sequentila order. The winding exhibits a higher series capacitance than a comparable rating continuous disk winding and a lower series capacitance than a comparable rating interlaced-disk winding, thereby making it suitable for use in a wide range of electrical systems.

I have found that the use of my Non-sequential Disk Winding may present some insulation and cooling problems in certain applications as the inner or low voltage winding of a relatively large transformer.

Accordingly, it is a further object of my invention to provide a disk winding particularly suited for use as the inner'or low voltage winding of a relatively large transformer.

SUMMARY OF THE INVENTION In accordance with one aspect of my invention l provide a relatively high series capacitance disk type winding which is constructed of a plurality of parallel conductors wound in at least one annular coil wherein mechanically adjacent turns of the conductors are electrically remote from one another. The winding is not interlaced inasmuch as each of the series circuits formed of the turns ofa conductor traverses each coil only once. The mechanically adjacent but electrically remote turns provide the winding with a relatively high series capacitance. The winding may be constructed to utilize zones of different series capacitance with the zone of higher series capacitance adjacent the line end of the winding, with the zone of lowest series capacitance in the middle of the winding and, if desired, with a zone or zones of intermediate series capacitance therebetween.

BRIEF DESCRIPTION OF THE DRAWINGS My invention will be better understood and its various objects and advantages will be more fully appreciated from the following description in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic diagram of a portion of an electric transformer having a low voltage, two-stranded, disk-type winding embodying my invention;

FIG. 2 is a schematic diagram of a portion of another two-stranded winding in accordance with my invention;

FIG. 3 is a schematic diagram of a three-stranded, disk-type winding embodying my invention;

FIG. 4 is a schematic diagram of a portion of another three-stranded winding in accordance with my invention;

FIG. 5 is a schematic diagram of a four-stranded, disk-type winding embodying my invention; and

FIG. 6 is a schematic diagram of a portion of another four-stranded winding in accordance with my invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, I have shown in crosssection in FIG. 1 a core type electric induction apparatus having a magnetic core 101 including plural parallel legs (only one of which is shown) upon each of which are mounted current conducting windings indicated generally by reference numeral 102. Each winding 102, in the case of a typical core type transformer, comprises an inner" or low voltage winding 110 closely surrounding the core 101 and a high voltage winding 11l concentrically surrounding the low voltage winding. The high voltage winding is disposed between a pair of static plates 112 and is a disk-type winding wound in accordance with my invention as disclosed and claimed in my heretofore noted copending patent application. The space between the low voltage winding and the core 101 is filled at least partially by a tubular insulating spacer 114. The radial space between the low voltage winding 110 and the high voltage winding 111 is referred to as the transformer main gap, and a tubular insulating sleeve 115 is provided in this space.

It will be understood as the description proceeds that while I have shown for the purposes of illustration a core type transformer having a primary winding section and a secondary winding section on a core leg, my invention is equally applicable to other types of transformers and to reactors or other apparatus including high voltage inductive windings whether of the single phase or multiphase type. My invention itself concerns more particularly of the structure and configuration of the inner" or low voltage" windings. In the case illustrated the invention concerns the low voltage primary winding 110 of the transformer. Reference will be had hereinafter, therefore, more particularly to the crosssectional view of FIG. 1. As can be seen therein the low voltage winding includes 12 serially connected annular coils 120, 121, 122, 123, 124, 125, 126, 127, 128,129, 130 and 131. It should be noted at this point that the winding may be made up of any number of coils as may be desired in accordance with the voltage rating thereof.

As previously noted continuous disk windings exhibit a less-than-desirable surge voltage distribution characteristic. Interlaced disk windings exhibit increased series capacitance over comparable continuous disk windings owing to the fact that interlacing insures that mechanically adjacent turns are electrically remote from one another. However, interlaced disk windings are relatively expensive and voluminous particularly plural strand disk windings since in such windings each conductor traverses a single coil more than once. It is such plural traversals that increase winding cost and necessitate voluminous insulation.

A plural-strand, disk-winding in accordance with my invention utilizes turns which are mechanically adjacent while electrically remote without necessitating plural traverses of a single coil and thus provide the advantages of interlacing (e.g., higher series capacitance) without its disadvantages (e.g., high cost, size etc.).

The first or end coil in a winding in accordance with my invention is wound of parallel conductors, with the first N turns thereof being formed of only one conductor (N being an integer). In the embodiment shown in FIG. 1, N is equal to 11 and a winding is formed of parallel conductors a and b.

As can be seen, conductor a is connected to a terminal Tl which forms a line end of the winding 110. The coil is wound rotationally inward for 11 turns of conductor a, i.e., turns 1a through 11a. The next turn wound is the first turn, 1b, of the other conductor, b. The first turn of conductor b is connected to line terminal T1. The remaining turns forming coil 120 are formed by winding alternate turns of each of the a and b conductors, starting with the a conductor and ending with the b conductor. As can be seen those turns comprise in the following order: turns 12a, 2b, 130, 3b, 14a, 4b, 15a, 5b, 16a, 6b, 17a and 17b.

Coil 121 is serially connected to coil 120 and is wound rotationally outward with the turns of conductors a and b continuing to alternate sequentially, starting with the next successive turn of conductor a, i.e., turn 18a, until a total of M turns of each conductor are wound. In the embodiment shown in FIG. 1 M is equal to 14 (i.e., there are 14 turns of each conductor wound following the first turn of conductor b). It should be pointed out that M can be any integer such that the sequential alternation of conductors a and b following the first turn of the second conductor can encompass as many or as few coils in the winding as desired.

As should be appreciated from the point in the coil 120 at which the turns begin alternating there is an equivalent of N-l (i.e., IO) electrical turns between each turn of the a conductor and the mechanically adjacent and succeeding turn of the b conductor. Due to the fact that the mechanically adjacent turns are electrically remote from one another, high series capacitance results in this portion of the winding.

Since a major portion of the surge voltage will initially appear across the end coils of a disk winding, increasing the series capacitance in that portion of the winding will improve the windings surge voltage sustaining ability. In accordance with my invention N can be any integer greater than 1 and the higher the value of N the greater the series capacitance of the end portion of the winding. Accordingly, the surge voltage sustaining ability of a winding can be tailored to meet design objectives by the proper selection of the value of N.

I have found that the voltage difference between mechanically adjacent turns of the a and b conductors decreases toward the interior to the winding particularly when M is large. Therefore, where M is relatively large, even though mechanically adjacent turns remain electrically remote (i.e., there are N-l electrical turns between the a conductor and the mechanically adjacent succeeding b conductor) an interior portion of a winding in accordance with my invention will exhibit a series capacitance comparable to that of a continuous disk winding while the end portion thereof will exhibit a much higher series capacitance.

In many applications such a winding may be acceptable, in other applications it would be desirable to increase the series capacitance in midportions of the winding as well as in the end portions.

The winding shown in FIG. 1 accomplishes that end by changing the electrical spacing between mechanically adjacent turns in a manner similar to that which is done at the line end of the winding. To that end, immediately after the Mth alternately wound turn of the b conductor, i.e., turn b, a single turn, 26a, of the a conductor is wound, followed by R turns of the b conductor, i.e., turns 16b through 21b. R is an integer which is normally equal to or smaller than the interger M and in the embodiment shown R equals 6. The portion of the winding formed by the R turns 16b through 21b is hereinafter referred to as a .transition zone 132. Turn 21b forms the outermost turn of coil 121.

Coil 122 is serially connected to coil 121 and is wound rotationally inward with the turns of conductors a and b alternating sequentially throughout, starting with the next. electrically succeeding turn of the a conductor, i.e., turn 27a.

' Coil 123 is serially connected to coil 120 and is wound rotationally outward with the turns of conductors a and b continuing to alternate sequentially starting withthe next succeeding turn of the a conductor until a total of S turns of each conductor are wound from the transition zone 132 onward. In the embodiment shown in FIG. 1 S equals 20, i.e., there are alternating turns of each conductor wound following the Rth turn of the b conductor.

It should be noted that S can be any integer such that the sequential alternation of conductors a and b encompasses as many or as few coils in the winding as desired.

In the portion of the winding approaching the Mth alternate turn of each conductor the voltage drop between mechanically adjacent turns thereof approaches zero (due to the transfer of energy between the conductors via the tum-to-turn capacitance). Immediately after the transition zone 132 the two conductors, which heretofore had approached the potential of one another, are electrically displaced from one another by N-R turns, i.e., there is an equivalent of five electrical turns between each turn of the a conductor and the mechanically adjacent and succeeding turn of the b conductor. The electrical displacement of the mechanically adjacent turns results in an increase in the series capacitance of this portion of the winding.

Immediately succeeding the Sth alternately wound turn of conductor b, i.e., turn 41b, there is a single turn, 47a, of the a conductor followed by another transition zone 133 composed of T turns of the b conductor, i.e., turns 42b through 47b. T is an integer which is normally equal to or smaller than the integer R and in the embodiment shown T equals 6. Turn 47b forms the outermost turn of coil 123. Coil 124 is serially connected to coil 123 and is wound rotationally inward with the turns of conductors a and b alternating sequentially throughout starting with the next successive turn of the a conductor, i.e., turn 48a. The turns continue to alternate sequentially through serially connected coil 125.

In the portion of the winding immediately succeeding the second transition zone, zone 133, there is the equivalent of NR-'T+l electrical turns between each turn of the a conductor and the mechanically adjacent and succeeding turns of the b conductor. Since NR-T+l equals zero the portion of the winding immediately succeeding transition zone 133 is wound like a conventional two-strand, continuous-disk winding.

Coils 120 through 125 form one half of the winding and coils 126 through 131 form the other half thereof. The half of the winding composed of coils 126 through 131 is wound in a similar manner as coils through and coils 126 through 131 are mirror images of coils 120 through 125, respectively, save for the fact that conductors a and b are interchanged. 7

FIG. 2 shows three coils, 120', 121 and 122' of an end portion of an alternative two-strand embodiment of my invention. In that embodiment there is a direct transition between the line end portion of the winding (where there are the equivalent of 10 electrical turns between each turn of the a conductor and the mechanically adjacent and succeeding turn of the b conductor) and the interior of the winding which is wound as a continuous disk. To that end, immediately succeeding the last turn of the b conductor in the portion of coil 121' where N equals 11, i.e., turn 13b, there is wound a single turn of the a conductor, turn 24a, immediately followed by R turns of the b conductor, where R equals N. Coil 122' is serially connected to coil 121' and is wound as a two-strand continuous disk.

FIG. 3 is a schematic diagram of the three strand disk winding in accordance with my invention.

As can be seen the winding comprises eight coils, 140, 141, 142, 143, 144, 145, 146 and 147 which are wound in alternate rotational directions and are serially connected between a pair of line terminals T3 and T4.

The end coil, 140, is wound of alternate conductors, a, b and c in the following order: conductor a is connected to the line terminal T3 and is wound rotationally inward through N equals 3 turns. The next succeeding rotationally inward wound turn of coil is the first turn of conductor b, which conductor is also connected to terminal T3. Immediately succeeding turn lb there are wound rotationally inward M alternate turns of each of the conductors a conductor, b, starting with the next succeeding the of the a conductor. conductor. the embodiment shown in FIG. 3 M equals N-l The next succeeding rotationally inward wound turn of coil 140 is the first turn of conductor c, which conductor is also connected to terminal T3. Immediately succeeding turn 1c there are wound rotationally inward P alternate turns of each of the conductors a, b and 0, starting with the next succeeding turn of the a conductor. As can be seen the turns alternate in this manner throughout serially connected coils 141, 142 and 143.

Coils 140 through 143 form one half of the winding and coils 144 through 147 form the other half thereof. The half of the winding composed of coils 144-147 is wound in similar manner as coils 140-143, and coils 144-147 are mirror images of coils 140 through 143, respectively, save for the fact that conductors a and c are interchanged.

The winding shown in FIG. 3 is characterized by the fact that there are the equivalent of N-l (i.e., two) electrical turns between each turn of the a conductor and the mechanically adjacent and succeeding turn of the b conductor and between each turn of the b conductor and the mechanically adjacent succeeding turn of the c conductor. This ensures that the winding exhibits a relatively high series capacitance at the line end thereof.

The winding shown in FIG. 3 does not contain any portions wound as a continuous disk. If a transition(s) to a continuous disk portion is desired, it can be effec tuated in many ways, one such way being shown in FIG. 4.

Before describing FIG. 4 it is to be understood that any plural-strand winding in accordance with my invention may be constructed with any number of electrical turns separating mechanically adjacent turns (i.e., with N equal to any integer) and with or without transitions to portions having fewer electrical turns separating mechanically adjacent turns.

FIG. 4 shows four coils, namely, 140, 141', 142' and 143' of an end portion of an alternative three-strand embodiment of my invention. In that embodiment there is a direct transition between the line end portion of the winding (where there are the equivalent of two electrical turns between a turn of the a conductor and the mechanically adjacent and succeeding turn of the b conductor and between a turn of the b conductor and the mechanically adjacent and succeeding turn of the c conductor) and the interior of the winding which is wound as a continuous disk winding. To that end, immediately succeeding the last turn of the c conductor in the portion of the coil 142' where N equals 3, i.e., turn 100, there is wound a single turn of a conductor, turn a, immediately followed by R equals M equals N1 alternate turns of the b and c conductors starting with the b conductor. Immediately succeeding the Rth alternate turn of the c conductor, i.e., turn 120, there is wound in the following order: the next succeeding turn of the b conductor, turn 15b and N=R+I=M+l turns of the c conductor. Coil 143' is serially connected to coil 142' and is wound as a continuous disk winding.

FIG. 5 is a schematic diagram of a four-stranded disk winding in accordance with my invention. As can be seen the winding comprises eight coils, namely, 150, 151, 152, 153, 154, 155, 156 and 157 which are wound in alternate rotational directions and are serially connected between a pair of line terminals T5 and T6.

The end coil, 150, is wound of four conductors, a, b, c and d in the following order: conductor a is connected to the line terminal T5 and is wound rotationally inward through N equals 3 turns. The next succeeding rotationally inward wound turn of coil 150 is the first turn of the b conductor, turn lb, which conductor is also connected to terminal T5. Immediately succeeding turn 1b there are wound rotationally inward M alternate turns of each of the conductors a and b, starting with the next succeeding turn of the a conductor. In the embodiment shown in FIG. 5 M equals N-l equals 2. The next succeeding rotationally inward wound turn of coil is the first turn of the c conductor, turn 1c, which conductor is also connected to terminal T5. Immediately succeeding turn 10 there are wound rotationally inward P alternate turns of each of the conductors a, b and 0, starting with the next succeeding turn of the a conductor i.e., turn 6a, followed by the first turn of the d conductor, turn 1d. Conductor d is also connected to terminal T5. From turn 1d onward in the winding there are Q alternate turns of each of the a, b, c and d conductors, starting with the a conductor with the equivalent of two electrical turns between a turn in the a conductor and the mechanically adjacent and succeeding turn of the b conductor, between a turn of the b conductor and the mechanically adjacent and succeeding turn of the c conductor and between a turn of the c conductor and a mechanically adjacent and succeeding turn of the d conductor.

As can be seen coils 150 through 153 form one half of the winding and coils 154 through 157 form the other half thereof. Coils 154 through 157 are the mirror images of coils 150 through 153, respectively, save for the fact that conductors a and d and conductors b and c are interchanged.

FIG. 6 shows four coils, namely, 150', 151, 152' and 153' of an end portion of an alternative four-strand embodiment of my invention. In that embodiment there is a direct transition between the line end portion of the winding (where there are the equivalent of two electrical turns between a turn of the a conductor and the mechanically adjacent and succeeding turn of the b conductor, between a turn of the b conductor and the mechanically adjacent succeeding turn of the c conductor and between a turn of the c conductor and the mechanically adjacent and succeeding turn of the d conductor) and the interior of the winding which is wound as a continuous disk winding. To that end, immediately succeeding the last turn of the d conductor in the portion of the coil 152' where N equals 3, i.e., turn 8d, there is wound a single turn of the a conductor, 15a, immediately followed by R equals M equals N-l alterante turns of the b, c and d conductors starting with the b conductor. Immediately succeeding the Rth alternate turn of the d conductor, i.e., turn 10d, there is wound in the following order the next succeeding turn of the b conductor, turn 15b, R equals M alternate turns of the c and d conductors starting with the c conductor, the next succeeding turn of the c conducotr, turn 15c, and N turns of th d conducotr. Serially connected coil 153 is wound as a continuous disk winding.

While I have shown and described a particular embodiment of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from my invention in its broader aspects; and I, therefore, intend herein to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a high series capacitance inductive winding having a first end terminal and including at least one annular coil including a plurality of turns formed of a plurality of parallel connected electrical conductors, each conductor of which traverses said coil in a series circuit only once, an improved arrangement of turns starting with the first end terminal comprising the following order:

a. N turns of a first conductor;

b. one turn of a second conductor;

0. M alternate turns of each of said first and second conductors starting with the first conductor,

(1. one turn of a third conductor;

e. P alternate turns of each of said first, second and third conductors starting with said first conductor and ending with said third conductor, said M, N and P being integers and said N being greater than one.

2. The winding as specified in claim 1 wherein said order additionally comprises:

f. one turn of a fourth conductor; and

g. Q alternate turns of each of said first, second, third and fourth conductors starting with said first conductor and ending with said fourth conductor, said Q being an integer.

3. The winding as specified in claim 1 wherein M equals N-l and wherein said order additionally comprises:

f. one turn of said first conductor;

g. R alternate turns of each of said second and said third conductors starting with said second conductor and ending with said third conductor;

h. one turn of said second conductor;

i. T=R+l turns of said third conductor;

j. S alternate turns of said first, said second, and said third'conductor starting with said first conductor and ending with said third conductor, said R and S being integers greater than one.

4. A winding as specified in claim 2 wherein M equals P equals N-l and wherein said order additionally comprises:

h. one turn of said first conductor;

i. R alternate turns of said second, said third and said fourth conductors starting with said second conductor and ending with said fourth conductor;

j. one turn of said second conductor;

k. R alternate turns of said third and said fourth conductors starting with said third conductor and ending with said fourth conductor;

1. one turn of said third conductor;

m. T=R+l turns of said fourth conductor;

n. S alternate turns of said first, said second, said third and said fourth conductors starting with said first conductor and ending with said fourth conductor, said R and S being integers greaterthan one.

I UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Pat nt 2.7%.617 Date-1 Julv 2 197R Invent fl JohriC. Crouse It is certified that error appears in the above-identified patent and that said Letters Patent are hereby'corrected as shown below:

Col. 2, lihe ll, delete non-sequential Col. 5, line 8, "f0" should be of Col. line 51,- "alternate" should be three 001. line 59,. "conduotor," should be and Col. line 60, the first occurrenoe V sh ould read Col. line'60, .before "the" second ocourrehoe insert Inline SO, "conduootr" should be conductor turn Col. 6, line 60, "conduotor' second occurrence delete.

Col. li ne 5l, "conducotr" should be a conductor Signed and sealed this 29th day of January 1974.

(SEAL).

Attest;

EDWARD M.F LETCHER,'JR. I RENE D. T EGTMEYERQ Y I Attest lng Officer Acting Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2 7L1.8 617 Dated Julv E 197% Inventor(s) John C. Grouse It is certified that error appears in the above-identified patent and that said Letters Patent are herebycorrected as shown below:

. Col. 2, line 11, delete non-sequential Col. 5, line 8, "f0" should be or Col. line 51, "alternate" should be three Col. line 59, "conductor," should be and Col. line 60, "the" first occurrence should read I turn Col. 6, line 60, "conductor" second occurrence delete.

Col. line 60, before "the" second occurrence insert In- Col. line 50, "conducotr" should be conductor Col. line 51, "conducotr" should be conductor Signed and sealed this 29th day of January 1974.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. RENE .D. TEGTMEYER Attesting Officer Acting Commissioner of Patents 

1. In a high series capacitance inductive winding having a first end terminal and including at least one annular coil including a plurality of turns formed of a plurality of parallel connected electrical conductors, each conductor of which traverses said coil in a series circuit only once, an improved arrangement of turns starting with the first end terminal comprising the following order: a. N turns of a first conductor; b. one turn of a second conductor; c. M alternate turns of each of said first and second conductors starting with the first conductor, d. one turn of a third conductor; e. P alternate turns of each of said first, second and third conductors starting with said first conductor and ending with said third conductor, said M, N and P being integers and said N being greater than one.
 2. The winding as specified in claim 1 wherein said order additionally comprises: f. one turn of a fourth conductor; and g. Q alternate turns of each of said first, second, third and fourth conductors starting with said first conductor and ending with said fourth conductor, said Q being an integer.
 3. The winding as specified in claim 1 wherein M equals N-1 and wherein said order additionally comprises: f. one turn of said first conductor; g. R alternate turns of each of said second and said third conductors starting with said second conductor and ending with said third conductor; h. one turn of said second conductor; i. T R+1 turns of said third conductor; j. S alternate turns of said first, said second, and said third conductor starting with said first conductor and ending with said third conductor, said R and S being integers greater than one.
 4. A winding as specified in claim 2 wherein M equals P equals N-1 and wherein said order additionally comprises: h. one turn of said first conductor; i. R alternate turns of said second, said third and said fourth conductors starting with said second conductor and ending with said fourth conductor; j. one turn of said second conductor; k. R alternate turns of said third and said fourth conductors starting with said third conductor and ending with said fourth conductor; l. one turn of said third conductor; m. T R+1 Turns of said fourth conductor; n. S alternate turns of said first, said second, said third and said fourth conductors starting with said first conductor and ending with said fourth conductor, said R and S being integers greater than one. 